#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;
int main() {
	string word1;
	string word2;
	cin >> word1;
	cin >> word2;
	int n1 = (int)word1.length();
	int n2 = (int)word2.length();
	vector<vector<int>> dp(n1 + 1, vector<int>(n2 + 1, 0));
	for (int i = 0; i <= n1; i++) dp[i][0] = i;
	for (int j = 0; j <= n2; j++) dp[0][j] = j;
	for (int i = 1; i <= n1; i++) {
		for (int j = 1; j <= n2; j++) {
			if (word1[i - 1] == word2[j - 1]) {
				dp[i][j] = dp[i - 1][j - 1];
			}
			else {
				dp[i][j] = min(dp[i - 1][j] + 1, min(dp[i][j-1]+1, dp[i-1][j-1]+1));
			}
		}
	}
	cout << dp[n1][n2];
	return 0;
}